package bintree.map_set.leetcode;

import java.util.*;

public class newke_BadKey {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        String expectedStr = null;
        String actualStr = null;
        while (scanner.hasNextLine()){
            expectedStr=scanner.nextLine();
            actualStr=scanner.nextLine();
        }
        expectedStr=expectedStr.toUpperCase();
        actualStr=actualStr.toUpperCase();
        Set<Character> set = new HashSet<>();
        for (int i = 0; i < actualStr.length(); i++) {
            set.add(actualStr.charAt(i));
        }
        Set<Character> single =new HashSet<>();
        for (int i = 0; i < expectedStr.length(); i++) {
            char c =expectedStr.charAt(i);
            if (!set.contains(c)){
                if (single.add(c)){
                    System.out.println(c);
                }
            }
        }
    }
}
